Google announced quite a few projects will be shutting down on their end in the next several months, and the CalDAV API will become one of those projects on September 16th for most developers. However, a few developers will be "whitelisted" and will be allowed to continue to use the CalDAV email protocol.
The good news for Windows Phone users is that Microsoft will be one of those developers on that whitelist, according to what Google told ZDNet.com today. You may remember that Microsoft is currently working to support both CalDAV and CardDAV protocols for a future version of Windows Phone that would allow those devices to connect directly to Googles Gmail accounts.
Google was going to cut off adding new Windows Phone devices via the Exchange Active Sync protocol at the end of January 2013 but at the last minute, Google extended that deadline to July 31st so that Microsoft could adapt Windows Phone for the CalDAV and CardDAV. EAS support was cut off for new Windows 8 and Windows RT PCs on January 31st as planned, although Microsoft did offer workarounds for users who still want to connect to their Gmail accounts.
Source: ZDNet.com | Image via Google